Fluid control systems including a regeneration capability, that is, the ability to direct some of the fluid exhausted from a contracting chamber of a double acting actuator to an expanding chamber thereof to provide an extension speed greater than that provided by pump flow only, are well known. One common type of regeneration valve is disposed between the main directional control valve and the actuator to provide a quick drop feature for actuators driven in one direction by gravity loads. One of the problems associated with having a regeneration valve between the main control valve and the actuator is that the operator has little or no control over the amount of regenerated fluid recirculated from the contracting chamber to the expanding chamber. Moreover, such regeneration valves are frequently triggered to their regeneration position automatically when the flow rate of the fluid expelled from the contracting chamber exceeds a predetermined flow rate such that regeneration takes place only under certain operating conditions.
Reference Poppe et al U.S. Pat. No. 5,370,038 issued Dec. 6, 1994 to Caterpillar Inc., which discloses a remotely controlled regeneration circuit for a hydraulic system utilizing a directional control valve and a separate, remotely controlled regeneration valve. However, providing a separate regeneration valve is a generally expensive and complex alternative.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.